public RefundResponse HandleRefund(string invoiceNumber, List <ICartItem> cartItems) { var result = new RefundResponse(); try { var api = new Api(CurrentConfiguration); foreach (var cartItem in cartItems) { api.AddArticleNumber(cartItem.Quantity, cartItem.Reference); } result.InvoiceNumber = api.CreditPart(invoiceNumber); result.IsSuccess = true; return(result); } catch (Exception ex) { SetError(result, ex); } return(result); }